Just bought an 05 GT convertible. (Automatic) The rear end sounds terrible. Knew this when I bought it. It came with everything (brand new) to drop it to a 4.10 (I think) but I don't feel like rebuilding a rear end myself. There are a few avaiable at a decent price used.

My question is: What fits? Found another convertible 06 model, but this one has a v6. Can I use this in my GT? Is it the same?

Not sure what my car came with for stock gearing.

 

I think your GT has an 8.8" rear end while the V-6 probably has a 7.5". If so, the V-8 would probably be too much for the smaller rear end. Get yours rebuilt by a pro.

 

It would mount but the 7.5" open differential won't last long. Definitely a downgrade and will have to be replaced soon.

The 2005-10 V6 uses a 7.5" rear end rather than your stronger 8.8". It doesn't come with a tlok so you have one wheel getting the power. It doesn't take much to break one either.

Starting in 2011 all Mustangs have the 8.8 with tlok.

Sent from my SPH-L720 using IB AutoGroup

 

DO NOT!! put that POS 7.5 rear in your GT...
Not only a down grade but try to sell that car later on. lol.
And like Jim says, it won't last long with the V8.

 

The 7.5 was barely up to the task behind and 1982-85 GT, so, your 420 horse GT will bbq its *** in molasses, boy, in no time. They had to put an 8.8 behind the modern 11+ V6 b/c it was too much for the 7.5, after the gasping-fish 4.0 went dodo.

Just build it and do it once instead of twice like you propose.